According to Scott from this post:
We consider climbing sessions as ‘strength’ training. Since they fit closest to this category. As mentioned above the TP metrics do not really work well for strength training sessions especially when using hrTSS because heart rate is poor proxy for effort.
What I do is make standard TSS’s for strength and climbing. For General strength I do 50TSS/hour. For Max strength I do 75-80TSS/hour. For climbing I do 50TSS/hr for ARC training (below on sight level). 80TSS/hr for climbing at near max level. Count only time on the rock.